Не удается прочитать свойство 'mobileStepText' из неопределенного - ngxstepper

Question

Я получаю ошибку

Невозможно прочитать свойство 'mobileStepText' неопределенного при попытке использования ngx-stepper.

Ниже мой код:
Это прямой пример с этого сайта: Директива Angular Steppers для Angular Material .

Но это не работает.

<ngx-stepper #stepperDemo="stepper" [options]="options">
    <ngx-step [label]="'Select a campaign'">
      <ngx-step-body>
        <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Consectetur </p>
        <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Consectetur nobis</p>
        <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Consectetur nobis saepe </p>
        <p>Lorem ipsumsamus repellendus deserunt. Odio sit similique, labore </p>
      </ngx-step-body>
      <ngx-step-actions>
        <button md-button class="md-primary md-raised" (click)="selectCampaign()">Continue</button>
        <button md-button class="md-primary" (click)="stepper.back()">Cancel</button>
      </ngx-step-actions>
    </ngx-step>
    <ngx-step [label]="'Publish the ad'">
      <ngx-step-body>
        <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Consectetur nobis saepe facere suscipit atque,
          sapiente, natus mollitia ipsum odit accusamus repellendus deserunt. Odio sit similique, labore maxime
          voluptatibus, eaque autem!</p>
      </ngx-step-body>
      <ngx-step-actions>
        <button md-button class="md-primary md-raised" (click)="stepper.next()">Complete</button>
        <button md-button class="md-primary" (click)="stepper.back()">Back</button>
      </ngx-step-actions>
    </ngx-step></ngx-stepper>

.ts

import { Component, OnInit, ViewChild } from '@angular/core';
import { MatStepper } from '@angular/material';
import {FormBuilder, FormGroup, Validators} from '@angular/forms';
import { NgxStepperModule, NgxStepperComponent } from 'ngx-stepper';
@Component({
  selector: 'app-registration',
  templateUrl: './registration.component.html',
  styleUrls: ['./registration.component.sass']
})
export class RegistrationComponent implements OnInit {
  @ViewChild('stepperDemo')
public steppers: NgxStepperComponent;

public selectCampaign(): void {
  this.steppers.showFeedback('Checking, please wait ...');
  this.steppers.next();
}

  constructor(private _formBuilder: FormBuilder) { }

  ngOnInit() {

}
}

Что я могу с этим поделать?

Answer 1

Вы должны определить опции в своем классе RegistrationComponent

options: StepperOptions = {
    linear: false,
    mobileStepText: false,
    alternative: true,
    vertical: false
  };